Northland MP Winston Peters has called on the Prime Minister to attach a choke chain to Primary Industries Minister Nathan Guy, and to use it, after news that Mr Guy has his officials developing an Import Health Standard for animal manure.
"Few things this National government does surprises me anymore, but allowing in European animal manure to grow mushrooms really does beat all," Mr Peters said.
"We're not short of what comes out the back of farm animals, and if this wasn't so short-sighted and stupid it would almost be comedic.
Our farmers are under siege from all and sundry on the question of animal excreta. They are trying to deal with it, so why on earth import more of it from offshore?"
Mr Guy had said the risk of exposing farmers and growers to an outbreak of something economically crippling, like foot and mouth disease, was low, but Mr Peters saw no sense in raising the risk given the country's "already leaky biosecurity system".
The imported wastes of farm animals was as high a risk as could possibly be imagined, he said.
"We're doing this because a misguided Mr Guy believes: 'As a country that operates under basic fair trading principles, the local production of any substance does not preclude the importation of similar substances which produce higher quality mushrooms with substantially better yields'," he said.
"In short, this minister is arguing that another country's farm animal scatology grows mushrooms faster than ours. That's so ridiculous that the Prime Minister needs to get a handle on this minister, and fast.
"You'd also expect in this era of user pays that the importer would be footing the bill for this work. Unbelievably, MPI is treating this as a high priority, so taxpayers are paying for bureaucrats to develop it. That is a wasteful scandal.
"Officials were even sent to a manure production plant in the Netherlands while more information was gathered and the 'risk assessment' revisited. What hidden influences came to bear for this taxpayer-funded tour to Europe to take place?
"It's time for farmers to tell Mr Guy and Mr English that this idea is just scatology."